Fuel cell and fuel cell stack

Abstract

The invention relates to a fuel cell stack (1), comprising: —bipolar plates (10), each having an active region (13a), wherein a surface of the bipolar plate is formed non-profiled at least in the active region (13a), —a membrane electrode assembly (20), arranged between two bipolar plates (10), and—a gas distribution layer (30) arranged between the membrane electrode assembly (20) and at least one of the bipolar plates (10), wherein the gas distribution layer (30) comprises a porous flow body (31). It is provided that the gas distribution layer (30) includes recesses (32) in the active region (13a).

The invention claimed is: 
     
       1. A fuel cell stack, comprising:
 first and second bipolar plates, the first and second bipolar plates including an active region, wherein each of the first and second bipolar plates includes a first plate half that is planar and a second plate half that is contoured, wherein the second plate half of the first bipolar plate faces toward the first plate half of the second bipolar plate; 
 a membrane electrode assembly positioned between the first and second bipolar plates; 
 a first gas distribution layer positioned between the membrane electrode assembly and the second plate half of the first bipolar plate, wherein the first gas distribution layer includes a porous flow body and does not include recesses in the active region; and 
 a second gas distribution layer positioned between the membrane electrode assembly and the first plate half of the second bipolar plate, wherein the second gas distribution layer includes a porous flow body and recesses in the active region, wherein the porous flow body of the second gas distribution layer includes a metallic material and wherein each of the first and second bipolar plates includes coolant channels between the respective first and second plate halves. 
 
     
     
       2. The fuel cell stack according to  claim 1 , wherein the recesses of the second gas distribution layer include discrete channels. 
     
     
       3. The fuel cell stack according to  claim 2 , wherein the discrete channels extend longitudinally over the active region. 
     
     
       4. The fuel cell stack according to  claim 1 , wherein the recesses of the second gas distribution layer include passage openings extending through the thickness of the second gas distribution layer. 
     
     
       5. The fuel cell stack according to  claim 1 , wherein the porous flow body of the second gas distribution layer has a macroporous structure. 
     
     
       6. The fuel cell stack according to  claim 1 , wherein the porous flow body of the second gas distribution layer is bonded to the first plate half of the second bipolar plate. 
     
     
       7. The fuel cell stack according to  claim 1 , wherein the membrane electrode assembly includes a respective gas diffusion layer adjacent to each of the first and second gas distribution layers, each of the gas diffusion layers having a porosity less than a porosity of the respective gas distribution layer. 
     
     
       8. The fuel cell stack according to  claim 1 , wherein the second plate half of the first bipolar plate faces a cathode side of the membrane electrode assembly. 
     
     
       9. A method of fabricating a fuel cell stack, comprising:
 positioning a membrane electrode assembly between first and second bipolar plates, the first and second bipolar plates including an active region, wherein each of the first and second bipolar plates includes a first plate half that is planar and a second plate half that is contoured, wherein the second plate half of the first bipolar plate faces toward the first plate half of the second bipolar plate; 
 positioning a first gas distribution layer between the membrane electrode assembly and the second plate half of the first bipolar plate, wherein the first gas distribution layer includes a porous flow body and does not include recesses in the active region; and 
 positioning a second gas distribution layer between the membrane electrode assembly and the first plate half of the second bipolar plate, wherein the second gas distribution layer includes a porous flow body and recesses in the active region, wherein the porous flow body of the second gas distribution layer includes a metallic material and wherein each of the first and second bipolar plates includes coolant channels between the respective first and second plate halves. 
 
     
     
       10. The method according to  claim 9 , wherein the recesses of the second gas distribution layer include discrete channels. 
     
     
       11. The method according to  claim 10 , wherein the discrete channels extend longitudinally over the active region. 
     
     
       12. The method according to  claim 9 , wherein the recesses of the second gas distribution layer include passage openings extending through the thickness of the second gas distribution layer. 
     
     
       13. The method according to  claim 9 , wherein the porous flow body of the second gas distribution layer has a macroporous structure. 
     
     
       14. The method according to  claim 9 , wherein the porous flow body of the second gas distribution layer is bonded to the first plate half of the second bipolar plate. 
     
     
       15. The method according to  claim 9 , wherein the membrane electrode assembly includes a respective gas diffusion layer adjacent to each of the first and second gas distribution layers, each of the gas diffusion layers having a porosity less than a porosity of the respective gas distribution layer. 
     
     
       16. The method according to  claim 9 , wherein the second plate half of the first bipolar plate faces a cathode side of the membrane electrode assembly.